UPDATE 3-Cisco extends offer period for Tandberg bid

* Cisco extends offer until Nov. 18

* Tally not yet disclosed

* Cisco reiterates original terms, calls it 'a fair price' (Adds comments from shareholders, analyst)

By Richard Solem and Ritsuko Ando

OSLO/NEW YORK, Nov 9 (Reuters) - Cisco Systems Inc (CSCO.O) extended on Monday its $3 billion tender offer for Tandberg ASA (TAA.OL) by nine days, after some shareholders of the Norwegian videoconferencing company demanded a higher price.

Cisco, the largest U.S. network equipment maker, said it would extend its offer, originally due to expire on Monday, to Nov. 18, but the terms and conditions of its 153.50 crown-per-share offer would remain unchanged until then.

Analysts said they expect Cisco to sweeten its bid, possibly to around 160 crowns or 170 crowns. Tandberg shares were up 0.53 percent at 151.80 crowns on Monday and Cisco shares were up 0.3 percent at $23.90.

ABG Sundal Collier analyst Hallgeir Hollup said he believes that Tandberg, the world's leader in videoconferencing products, is worth more.

"We also believe that Cisco will hike the bid," he said.

Cisco did not disclose the tally of shareholders who had tendered their shares and those who hadn't, although groups representing around 30 percent of shareholders have publicly opposed the deal.

A spokesman for Cisco's Norwegian agent, Carnegie, told Reuters that information about how many shares were tendered would be released on Tuesday.

The U.S. company reiterated its statement that its offer represents a good premium and is backed by Tandberg's board of directors.

"We believe that we're paying a fair price for a quality asset," a Cisco spokeswoman said after announcing the extension.

Cisco Chief Executive John Chambers said last week that he believed the company could close the Tandberg deal but also raised the prospect of walking away, saying that there was no such thing as a "must have" deal.

KEY GROWTH AREA

While walking away is indeed an option, few analysts expect Cisco to opt for that, as it has repeatedly touted online videoconferencing as a key growth area.